It is well known that colored images can be formed by reacting an oxidized product of a primary aromatic color developing agent which is the oxidizing agent for exposed silver halide with a coupler to form indophenol, indoaniline, indamine, azomethine, phenoxazine, phenazine dyes and dyes related to these materials.
In this case, 5-pyrazolone, cyanoacetophenone, indazolone, pyrazolobenzimidazole and pyrazolotriazole based couplers have been used for forming magenta images.
In the past, the 5-pyrazolone based couplers have been used most widely and have been the subject of most research as magenta image forming couplers. However, the dyes formed with 5-pyrazolone based couplers have a secondary absorbance at about 430 nm and they are known to be a cause of color turbidity.
The pyrazolobenzimidazole skeleton disclosed in British Patent 1,047,612, the indazolone skeleton disclosed in U.S. Pat. No. 3,770,447 and the pyrazolo[5,1-c]-1,2,4- triazole skeleton disclosed in U.S. Pat. No. 3,725,067 have been proposed as magenta image forming skeletons with which there is little absorbance in the yellow region.
Furthermore, magenta couplers based on, for example, pyrazoloazoles such as the imidazo[1,2-b]pyrazoles, the pyrazolo[1,5-b][1,2,4]triazoles, the pyrazolo[1,5-b]-tetrazoles, the pyrazolo[1,5-b]benzimidazoles and the pyrazolopyrazoles have also been developed as magenta couplers which have little unwanted yellow absorbance and which have good color forming properties.
Furthermore, more recently couplers which produce cyan colors have also been developed with the same parent nuclei.
However, the fastness with respect to light of the azomethine dyes formed from such pyrazoloazole based couplers is comparatively low and it has not been possible to prevent satisfactorily the occurrence of color fading using the color image stabilizers (for PG,4 example, alkyl substituted hydroquinones) which have generally been used in the past.
Attempts have been made to resolve this problem by adding various compounds. For example, there are methods in which alkoxybenzene derivatives are added as disclosed, for example, in JP-A-59-125732 (U.S. Pat. No. 4,588,679), JP-A-60-262159 (U.S. Pat. No. 4,735,893, and U.S. Pat. No. 4,931,382), JP-A-61-282245, JP-A-62-244045, JP-A-62-44046 (U.S. Pat. No. 4,895,793), JP-A-62-273531 (U.S. Pat. No. 4,868,101), JP-A-61-158330 (U.S. Pat. No. 4,623,617), JP-A-63-95439 (U.S. Pat. No. 4,814,262), JP-A-63-95448, JP-A-63-95450 and JP-A-63-84548. (The term "JP-A" as used herein signifies an "unexamined published Japanese patent application"). The compounds disclosed in these specifications certainly have an excellent improving effect on light fastness in regions where the concentration of the dye which has been formed by color formation with the coupler is high (referred to hereinafter as high density regions).
However, the dyes formed from pyrazoloazole based couplers have especially low light fastness in regions where the concentration of the dye which has been formed by color formation with the coupler is low (referred to hereinafter as low density regions) and, with reflective type photosensitive materials in particular, this gives a strong cast and an undesirable balance with the fading of the other colors, and the improving effect on light fastness of the aforementioned alkoxybenzene derivatives is only slight in the low density regions and a better technique is required.
On the other hand, methods by which the yellow staining which is produced by 5-pyrazolone magenta couplers can be controlled and the light fastness of the colored image can be improved by using bis-phenol based compounds alone or by using bisphenol compounds and specified alkoxybenzene derivatives conjointly have been disclosed, for example, in JP-B-60-3173, JP-B-60-3174 (U.S. Pat. No. 4,174,220), JP-A-52-72225 (GB 1,529,908), JP-A-54-70830, JP-A-61-158333 and JP-A-62-24250. (The term "JP-B" as used herein signifies an "examined Japanese patent publication"). Although the compounds disclosed in the aforementioned patents are seen to inhibit yellow staining with 5-pyrazolone based magenta couplers and to strengthen the light fastness of the colored image, the effect achieved cannot be said to be satisfactory. Furthermore, application to pyrazoloazole based magenta couplers is proposed in European Patent 218,266, but here the improving effect in respect of color fading is poor.
Furthermore, methods involving the conjoint use of magenta couplers and ultraviolet absorbers and controlling the yellow staining which arises from the magenta coupler, and of improvement in respect of color fading by the conjoint use of alkoxybenzene based compounds have been disclosed, for example, in JP-A-50-87326, JP-A-55-50245, JP-A-54-73032 and JP-A-61-250644. In particular, the control of the yellow staining produced from the magenta coupler by the conjoint use of a pyrazoloazole based magenta coupler and an ultraviolet absorber, and the conjoint use of an alkoxybenzene based compound for improving the fading properties of the dye image have been proposed in JP-A-61-250644, but there is virtually no improving effect in respect of the fading of the dye image in the low density regions beyond the additive properties due to the conjoint use of these compounds.
In this sense, there is a demand for a technique which prevents color fading in light and which, in particular, prevents color fading in light in the low density regions.